Many commercial production processes utilize conveyer transported trays. In a process for preparing bakery products from yeast containing dough, trays are often utilized in "proofing" the dough. Proofing refers to the portion of the process wherein the yeast is activated and the dough is allowed to rise. In a commercial process for preparing bakery products, such as breads, rolls, doughnuts, pastries and the like, from dough, the dough may be mixed and formed and then placed on "proofing trays" for proofing. In order to ensure reproducible results in the proofing process, the proofing trays may be maintained in an environment of relatively constant temperature and humidity. In some commercial processes, the proofing trays may also be utilized to carry the dough to the oven or fryer where the dough is to be baked or fried to produce the bakery product.
In a prior art process utilized by the assignee of the present application, the proofing trays form part of an assembly line process for producing fried bakery products (doughnuts). Dough is mixed and extruded in a doughnut shape onto horizontally disposed trays. The dough is proofed by carrying the dough containing trays, suspended by their ends on serpentine vertical conveyer belts or chains, through a relatively constant temperature/humidity environment for a period of time sufficient to allow the dough to rise. The dough containing trays are held by pins on the conveyer belt or chain such that they may swing and therefore remain substantially horizontal as they move over the pulleys or sprockets and vertically through the constant temperature/humidity environment. This is commonly accomplished by maintaining the center of gravity of the tray and the dough being proofed below the center of the conveyor attachment pin. The apparatus which includes the conveyer belt and dough carrying trays, and maintains the relatively constant temperature/humidity environment is generally referred to as a "Proofer". The time in the Proofer is a function of the length of the conveyor and its linear speed.
At a next station, after proofing, the proofed extruded dough is removed from the trays and placed into a fryer for frying. The removal of the dough from the trays is accomplished by tipping the trays, causing the dough to fall off the trays into the fryer where the dough is fried to produce doughnuts. This is commonly accomplished by having a portion of the moving tray strike a stationary portion of the proofer structure causing the tray to invert. It is further known to maintain the tray in the inverted position and cause the tray surface supporting the dough to pass horizontally above a stationary member spanning most of its length that will peel off a proofed dough that might still be clinging to the tray and cause it to fall.
Alternately, in other processes known in the art, the proofed dough may be lifted off the trays by hand, with or without, the use of a spatula or other lifting device. The proofed dough may then be placed onto racks for baking to produced baked products.
In still other embodiments known in the art, the trays utilized in proofing the dough are also utilized to hold the proofed dough during a baking or frying process. Then, after baking or frying, the final bakery product is removed from the trays for packaging and/or sale.
In heretofore known commercial baking processes, such as those utilized by the assignee of the present application, the trays utilized to carry the dough during the proofing process ("proofing trays") are generally produced from stainless steel. The ends of the proofing trays include means for attaching the proofing tray to the vertically disposed belt or chain utilized in the proofer. In order to achieve circulation around the extruded dough, and through the tray, the dough holding surface of the tray is generally of mesh construction. In addition, the dough holding surface may be convexly bowed, with the center slightly higher than each edge, along the axis running between the ends of the tray.
In prior art processes, the dimensions of the proofing tray depend on the size of the dough product to be carried on the tray and the size of the proofer. Manufacturers make their machinery in varying capacities, commonly increasing it by processing increasing quantities of dough objects being processed at the same time. Thus a doughnut proofer tray might have a length suitable for carrying 2, 4, 6, 8, 10 or more doughnuts, rolls, etc. The width of the proofing tray is sufficient to hold the dough product to be proofed. For economy of manufacture, it would be highly desirable to use as many common parts as possible. Generally, proofing trays are designed to be utilized with a particular proofer, thus the length of the proofing tray depends on the size of the proofer, in particular the distance between the conveyer belt or chains which support the ends of the proofing tray. Thus, a commercial establishment with different size proofers must disadvantageously have different sizes of proofing trays in order to have trays for each proofer.
Unbaked, freshly mixed, yeast containing dough products are generally sticky. For this reason, the dough supporting surface of the proofing tray is generally coated with an anti-stick, food product safe, coating such as teflon. Although, the metal utilized in producing the proofing trays may last through years of the use, the anti-stick coating will wear at a more rapid rate, thus necessitating that the proofing tray be re-coated up to several times during their years of service. A tray with a capacity of 8 or more doughnuts might have to be removed, replaced and re-coated with a bare spot on only one doughnut location. In addition to the cost of re-coating the trays is the considerable cost of a technician's time to remove and replace the bare tray and the down time for the entire line. Trays being re-coated must necessarily be taken out of service, thereby disadvantageously disrupting the production process, and generally requiring a commercial establishment to have a back-up supply of proofing trays to substitute for the trays being re-coated. The need to have a back-up supply of trays disadvantageously increases the overall equipment cost of producing a bakery product, and in addition may disadvantageously increase storage and other overhead costs.